Publications by Wilfried Noell

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Multi-object spectroscopy (MOS) is a powerful tool for space and ground-based telescopes for the study of the formation and evolution of galaxies. This technique requires a programmable slit mask for astronomical object selection. We are engaged in a Europ ...

An experimental thermal characterization method is developed for high thermal conductivity thin films. The method utilizes Ta/Pt resistors on microfabricated free-standing thin film structures both for heating and temperature monitoring at different positi ...

A high-power LED-based illumination system has been developed as a replacement for the mercury arc lamps used in mask-aligner lithography. LEDs are arranged in a grid array and placed in the entrance aperture of individual reflectors. Those reflectors decr ...

We describe the performance of a reflective pulse-shaper based on a Micro-ElectroMechanical System (MEMS) linear mirror array. It represents a substantial upgrade of a preceding release [Opt. Lett. 35, 3102 (2010)] as it allows simultaneous piston and tilt ...

Refractive microlenses are nowadays widely used in optical systems. Characterizing their surface is essential to ensure their quality and to optimize their fabrication process. This is realized by optical surface profilers thanks to their vertical resoluti ...

Future space exploration will emphasize on cost effectiveness and highly focused mission objectives. Missions costs are directly proportional to its total weight, thus, the trend will be to replace bulky and heavy components of space carriers, communicatio ...

The uniformity of large microlens arrays in Fused Silica is governed by the production process. It comprises photolithographic patterning of a spin-coated layer of photoresist on a 200mm wafer with a molten resist reflow process and subsequent dry etching. ...

We have fabricated and characterized fully programmable diffraction gratings consisting of 64 silicon micro-mirrors. The mirrors are 700 mu m long and 50 mu m wide with a fill factor of 90%. They are actuated electrostatically and move down by 1.25 mu m wh ...

A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as ...

We present an in-detail description of the design, simulation, fabrication, and packaging of a linear micromirror array specifically designed for temporal pulse shaping of ultrashort laser pulses. The innovative features of this device include a novel comb ...

For the back-end microfabrication in integrated circuits and for the manufacturing of light emitting diodes, proximity mask-aligner lithography is still the tool of choice, due to its simplicity and low costs. However, the downscaling of functional element ...

MEMS-based programmable slit masks are developed for multi-object spectroscopy in astronomy. Devices with 2048 tiltable micromirrors were fabricated and tested, exhibiting very good surface flatness, high contrast and cryogenic operation ability. ...

We present a new approach of beam homogenizing elements based on a statistical array of concave cylindrical microlens arrays. Those elements are used to diffuse light in only one direction and can be employed together with fly’s eye condensers to generate ...

In multi-object spectrometers, field selectors, which are located in the focal plane of the telescopes, are required for the selection of astronomical objects, such as stars or faint galaxies. We present a two-dimensional micromirror array as a field selec ...

This paper will focus on the design, and first measurements of a cascaded in-plane parallel plate snap-in actuator. The actuator is based on a rather simple microfabrication process and can achieve a total displacement of several tenths of microns. Compare ...

In proximity mask aligner photolithography, diffraction of light at the mask pattern is the predominant source for image shape distortions such as line end shortening and corner rounding. One established method to mitigate the impact of diffraction is opti ...

Wilfried Noell

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Large micromirror array for generating programmable slit masks for Multi-Object Spectroscopy

Thermal Characterization of Polycrystalline CVD Diamond Thin Films

Spatial coherence properties of an LED-based illumination system for mask-aligner lithography

Spectral phase, amplitude, and spatial modulation from ultraviolet to infrared with a reflective MEMS pulse shaper

Correction of spherical surface measurements by confocal microscopy

MEMS for space

Improvements on the uniformity of large-area microlens arrays in Fused Silica

Optical characterization of fully programmable MEMS diffraction gratings

A dual-axis pointing mirror with moving-magnet actuation

Design, simulation, fabrication, packaging, and characterization of a MEMS-based mirror array for femtosecond pulse-shaping in phase and amplitude

Improving the resolution in mask-aligner lithography

Large micromirror array designed and tested for Multi-Object Spectroscopy

Fabrication and characterization of linear diffusers based on concave micro lens arrays

The two-dimensional array of 2048 tilting micromirrors for astronomical spectroscopy

Scalable cascaded snap-in actuators for large-stroke displacements

Computational rule-based approach for corner correction of non-Manhattan geometries in mask aligner photolithography